get system boot time in seconds in csharp

main.cs
using System.Diagnostics;

private static readonly DateTime StartTime = DateTime.UtcNow - TimeSpan.FromSeconds(PerformanceCounterType.PerformanceCounterTypeSystemUpTime.GetSystemUptime());

public static double GetSystemUpTimeInSeconds()
{
    using (var uptime = new PerformanceCounter("System", "System Up Time", true))
    {
        uptime.NextValue(); // Call this once to initialize the value
        return uptime.NextValue();
    }
}
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